A number of different electrical appliances utilize rechargeable battery packs for power. For example, electrical drills and saws and other electrical power tools very often utilize a rechargeable battery pack for power. A user may own more than one rechargeable battery pack so that a fresh battery pack may be installed while a spent battery pack is recharged.
Although rechargeable battery packs work well for their intended purpose, a fully recharged replacement battery pack may not be available. In addition, a user may be in a setting, such as a campsite, where power for a charger is not available.